Field of the Disclosure
The present disclosure relates to communications systems and more specifically to buffer flush optimization in Ethernet ring protection networks.
Description of the Related Art
A communication network may include network elements that route packets through the network. The communication network may be an Ethernet network.
In the G.8032 recommendation promulgated by the International Telecommunication Union Telecommunication Standardization Sector (ITU-T), Ethernet ring protection (ERP) switching is described with the aim of fast protection switching for ring topologies having physical loops while ostensibly avoiding logical loops at the Ethernet layer. Logical loops adversely affect network performance and operation and are undesirable for Ethernet networks. Specifically, G.8032 avoids logical loops in an Ethernet ring network by reserving so-called Ring Protection Links (RPL), which are linked to an RPL Owner Node and an RPL Neighbor Node at each end of the ring. When the Ethernet ring network is operating normally, RPLs block network traffic to avoid logical loops from forming. When an associated physical link in the Ethernet ring network fails, the RPL is activated to transmit (i.e., unblock) network traffic by the RPL Owner Node or the RPL Neighbor Node.
Additionally, ring nodes maintain a local buffer, known as a filtering database (FDB) that stores topology information about neighboring nodes in G.8032. When a topology change in the G.8032 network occurs, such as for a protection switch event, the topology information, typically stored in the form of media access control (MAC) addresses, is flushed. After flushing of the local buffers, each ring will begin to broadcast data frames until the MAC addresses are learned again for the new topology.
However, despite the G.8032 protocol, Ethernet ring networks may excessively flush local buffers upon a topology change, which is undesirable because of the excess network traffic generated as a result.